Various devices for transferring power in a vehicle transmission are known to those skilled in the art. One such device is a shifting collar utilized as part of a collar shift transmission. Collar shift transmissions utilize the shifting collar to engage various gears. In some collar shift transmissions, a pair of lever arms are utilized to allow a vehicle operator to manually select or change a gear.
Typically, the first lever arm is located in a console next to the vehicle operator. The second lever arm is connected to a yoke which is connected to the shifting collar. The first lever arm is connected to the second lever arm by, for example, a cable. Thus, in order to disengage or engage a gear the vehicle operator must apply a force to the first lever arm. The force is transmitted through the connector to the second lever arm which transmits the force to the yoke and to the shifting collar which then moves the shifting collar along a clutch shaft. An example of the collar shift transmission assembly described above and compatible with the present invention can be found in U.S. Pat. No. 7,406,888, the disclosure of which is hereby incorporated by reference.
The amount of force required to select a gear using a lever arm is determined by a variety of factors. Factors include the type of engagement between the shifting collar and a presently selected gear, the frictional forces between the shifting collar and the clutch shaft, and any torque the weight of the vehicle provides. Any or all of these factors can effect the amount of force a vehicle operator must provide to select a gear.
Those skilled in the art have attempted to reduce the amount and the variability of the force required to select a gear in collar shift transmissions. However, the prior art systems are complex and expensive. It would thus be desirable to provide an economic shifting collar apparatus which reduces the amount of force required to select a gear. It would also be desirable to provide a shifting collar apparatus which requires only the same amount of force to select a gear regardless of the position of the vehicle.